DOI: 10.3724/SP.J.1227.2012.00241

Journal of Arid Land 2012/4:3 PP.241-250

The impact of land use change on soil organic carbon and labile organic carbon stocks in the Longzhong re-gion of Loess Plateau

Land use change (LUC) is widely recognized as one of the most important driving forces of global carbon cycles. The soil organic carbon (SOC) and labile organic carbon (LOC) stores were investigated at arable land (AL), artificial grassland (AG), artificial woodland (AW), abandoned arable land (AAL) and desert steppe (DS) in the Longzhong region of the Loess Plateau in Northwest China. The results showed that conversions from DS to AL, AL to AG and AL to AAL led to an increase in SOC content, while the conversion from DS to AW led to a decline. The differences in SOC content were significant between DS and AW at the 20–40 cm depth and between AL and AG at the 0–10 cm depth. The SOC stock in DS at the 0–100 cm depth was 39.4 t/hm2, increased by 28.48% after cultivation and decreased by 19.12% after conversion to AW. The SOC stocks increased by 2.11% from AL to AG and 5.10% from AL to AAL. The LOC stocks changed by a larger magnitude than the SOC stocks, which suggests that it is a more sensitive index of carbon dynamics under a short-term LUC. The LOC stocks increased at 0–20 cm and 0–100 cm depths from DS to AW, which is opposite to that observed for SOC. The proportion of LOC to SOC ranged from 0.14 to 0.20 at the 0–20 cm depth for all the five land use types, indicating low SOC dynamics. The allocation proportion of LOC increased for four types of LUC conversion, and the change in magnitude was largest for DS to AW (40.91%). The afforestation, abandonment and forage planting on arable land led to sequestration of SOC; the carbon was lost initially after afforestation. However, the carbon sink effect after abandonment may not be sustainable in the study area.

Key words:carbon sequestration,labile organic carbon,land use,cultivation,abandonment,Loess Plateau

ReleaseDate:2014-07-21 16:17:39

Chen J Y, Sun B, Li Z P, et al. 2008. Pool size of soil or-ganic carbon and dynamics under different land use. Journal of Soil and Water Conservation, 22(1): 91−96.

Chen L D, Gong J, Fu B J, et al. 2007. Effect of land use conversion on soil organic carbon sequestration in the loess hilly area, Loess Plateau of China. Ecological Research, 22: 641−648.

Du F, Liang Z S, Xu X X, et al. 2007. The community bio-mass of abandoned farm land and its effects on soil nutrition in the loess hilly region of northern Shanxi, China. Acta Ecologica Sinica, 27(5): 1673−1683.

Foote R L, Grogan P. 2010. Soil carbon accumulation during temperate forest succession on abandoned low productivity agricultural lands. Ecosystems, 13: 795−812.

Guo L B, Gifford R M. 2002. Soil carbon stocks and land use change: a meta analysis. Global Change Biology, 8: 345−360.

Guo M, Zheng F L, He W X, et al. 2010. Variation of vegeta-tion diversity and its relationship with soil nutrient and enzyme ac-tivity in lands of different abandoned years in the loess hilly-gully region. Acta Pedologica Sinica, 47(5): 979−986.

Guo Z G, Zhang Z H, Xiao J Y, et al. 2002. Root system de-velopment ability of several alfalfa cultivars in the hilly and valley regions of Loess Plateau. Chinese Journal of Applied Ecology, 13(8): 1007−1012.

Hu Y L, Zeng D H, Fan Z P, et al. 2007. Effects of degraded sandy grassland afforestation on soil quality in semi-arid area of Northern China. Chinese Journal of Applied Ecology, 18(11): 2391−2397.

Institute of Soil Sciences, Chinese Academy of Sciences (ISSCAS). 1978. Physical and Chemical Analysis Methods of Soils. Shanghai: Shanghai Science Technology Press, 7−15.

Intergovernmental Panel of Climate Change (IPCC), 2007. In: Solomon S, Qin D, Manning M, et al. IPCC Climate Change: the Physical Science Basis. Cambridge: Cambridge University Press, 996.

Jia G M, Fang X W, Liu B R, et al. 2006. Size and activity of microbial biomass in vegetation restoration of abandoned arable land in central region of Loess Plateau, China. Journal of Desert Research, 26 (4): 580−584.

Laganière J, Angers D A, Paré D. 2010. Carbon accumulation in agri-cultural soils after afforestation: a meta-analysis. Global Change Biology, 16: 439–453.

Laik R, Kumar K, Das D K, et al. 2009. Labile soil organic matter pools in a calciorthent after 18 years of afforestation by dif-ferent plantations. Applied Soil Ecology, 42: 71−78.

Li C J, Li Y, Ma J, et al. 2010. Spatial heterogeneity of soil chemical properties between Haloxylon persicum and Haloxy-lon ammodendron populations. Journal of Arid Land, 2(4): 257−265.

Li X D, Wei L, Zhang Y C, et al. 2009. Effects of land use regimes on soil physical and chemical properties in the Longzhong part of Loess Plateau. Acta Prataculturae Sinica, 18(4): 103−110.

Li Y M, Cao G M, Wang Y S. 2006. Effects of reclamation on soil organic carbon in Haibei alpine meadow. Chinese Journal of Ecol-ogy, 25(8): 911−915.

Liu C, Ren Y L, He J S. 2009. Soil dissolved organic carbon decreased following 40-year grassland afforestation. Acta Scientiarum Natu-ralium Universitatis Pekinensis, 45(3): 511−518.

Liu H L, Zhang W H, Wang K. 2009. Effect of reclamation on soil properties of zonal and intrazonal grasslands in agro-pastoral ecotone. Transactions of the Chinese Society of Agricultural Engi-neering, 25(10): 272−277.

Liu M Y, Chang Q R, Qi Y B, et al. 2010. Soil organic carbon and particulate organic carbon under different land use types on the Loess Plateau. Journal of Natural Resources, 25(2): 218−226.

Luo G P, Xu W Q, Chen X. 2005. Effect of different land-use systems on soil properties in the alluvial plain-oasis in the arid land. Acta Geographica Sinica, 60(5): 779−790.

Lützow M V, Kögel-Knabner I, Ekschmitt K, et al. 2006. Stabilization of organic matter in temperate soils: mechanisms and their relevance under different soil conditions–a review. European Journal of Soil Science, 57: 426–445.

Morari F, Lugato E, Berti A, et al. 2006. Long-term effects of recommended management practices on soil carbon changes and sequestration in northeastern Italy. Soil Use and Management, 22: 71−81.

Nelson D W, Sommers L E. 1982. Total carbon, organic carbon, and organic matter. In: Page A L, Miller R H, Keeney D R. Methods of Soil Analysis, Agronomy, part 2. 2nd ed. Madison, WI: ASA and SSSA, 539–577.

Paul K I, Polglase P J, Nyakuengama J G, et al. 2002. Change in soil carbon following afforestation. Forest Ecology and Man-agement, 168 (1–3): 241−257.

Poeplau C, Don A, Vesterdal L, et al. 2011. Temporal dynam-ics of soil organic carbon after land-use change in the temperate zone-carbon response functions as a model approach. Global Change Biology, 17: 2415–2427.

Purakayastha T J, Chhonkar P K, Bhadraray S, et al. 2007. Long-term effects of different land use and soil management on various organic carbon fractions in Inceptsol of subtropical India. Australian Journal of Soil Research, 45(1): 33−40.

Raiesi F. 2012a. Soil properties and C dynamics in abandoned and cultivated farmlands in a semi-arid ecosystem. Plant and Soil, 351: 161−175.

Raiesi F. 2012b. Land abandonment effect on N mineralization and microbial biomass N in a semi-arid calcareous soil from Iran. Jour-nal of Arid Environments, 76: 80−87.

Rong L, Li S J, Li X W, et al. 2011. Carbon dynamics of fine root (grass root) decomposition and active soil organic carbon in various models of land use conversion from agricultural lands into forest lands. Acta Ecologica Sinica, 31(1): 137−144.

Su Y Z, Liu W J, Yang R, et al. 2009. Carbon sequestration effect following retirement of degraded croplands into alfalfa forage land in the middle of Hexi Corridor region, Northwest China. Acta ecologica sinica, 29(12): 6385−6391.

Tang G Y, Li K, Sun Y Y, et al. 2010. Soil labile organic car-bon contents and their allocation characteristics under different land uses at dry-hot valley. Environmental Science, 31(5): 1365−1371.

Wang B, Liu G B, Xue S, et al. 2011. Changes in soil phys-ico-chemical and microbiological properties during natural succes-sion on abandoned farmland in the Loess Plateau. Environmental Earth Sciences, 62: 915−925.

Wang F, Xiao H L, Su Y Z, et al. 2011. Changes of soil quality after reclamation in oasis saline meadow in Linze, Gansu, China. Journal of Desert Research, 31(3): 723−728.

Wang L L, Song C C, Ge R J, et al. 2009. Soil organic carbon storage under different land-use types in Sanjiang Plain. China En-vironmental Science, 29(6): 656−660.

Wang X L, Guo S L, Ma Y H, et al. 2007. Effects of land use type on soil organic C and total N in a small watershed in loess hilly-gully region. Chinese Journal of Applied Ecology, 18(6): 1281−1285.

Wei J, Liu W G, Cheng J M, et al. 2011. Dynamics of soil organic carbon storage following restoration of grassland on Yunwu Mountain. Acta Ecologica Sinica, 31: 271−275.

Wu H B, Guo Z T, Peng C H. 2003. Land use induced changes of organic carbon storage in soils of China. Global Change Biology, 9: 305–315.

Wu J G, Zhang X Q, Xu D Y. 2004. Changes in soil labile organic car-bon under different land use in the Liupan mountain forest zone. Acta Phytoecologica Sinica, 28(5): 657−664.

Xu M G, Yu R, Sun X F, et al. 2006. Effects of long-term fertilization on labile organic matter and carbon management index (CMI) of the typical soils of China. Plant Nutrition and Fertilizer Science, 12(4): 459−465.

Yang W Z, Shao M A. 2000. Research on Soil Water Content at the Loess Plateau. Beijing: Science Press, 4–11.

Yang Y S, Xie J S, Sheng H, et al. 2009. The impact of land use/cover change on soil organic carbon stocks and quality in mid-subtropical mountainous area of southern China. Journal of Geographical Sciences, 19: 49−57.

Zhang E H, Huang G B. 2002. Limited factors and solutions of agri-cultural sustainable development in Loess Plateau of Gansu prov-ince. Journal of Soil and Water Conservation, 16(5): 9−13.

Zhang J H, Li G D, Nan Z R, et al. 2009. Temporal and spatial distribution of soil organic carbon under different land uses in the middle reaches of Heihe River. Journal of Lanzhou University: Natural Sciences, 48(4): 66−73.

Zhu B B, Li Z B, Li P, et al. 2010. Soil erodibility, microbial biomass, and physical-chemical property changes during long-term natural vegetation restoration: a case study in the Loess Plateau, China. Ecological Research, 25: 531−541.

Zhu Z J, Jiang P K, Xu Q F. 2006. Study on the active organic carbon in soil under different types of vegetation. Forest Research, 19(4): 523−526.